The present invention relates to a control system for a steering system, and more particularly to a control system for determining a rejection command based on hand wheel acceleration and road wheel frequency.
Vehicles are subjected to some degree of disturbance in the front road wheels. In one example, road wheel disturbance may be caused by variations in brake disk thickness, which is referred to as brake judder. The variation in brake disk thickness may create a harmonic modulation of a braking force during braking of the vehicle, which in turn may be transmitted to a steering column and a hand wheel of a steering system. The vibrations created in the hand wheel may be detected by a driver. Some approaches currently exist for reducing and rejecting road wheel disturbance. However, while they might be relatively effective at rejecting road wheel disturbance at higher vehicle speeds, these approaches may not be as effective if the vehicle is operating at relatively lower vehicle speeds. In other examples, road wheel disturbances may also be caused by imbalance, tire non-uniformity, or brake disk thermal effects.